function S = sumy(A)
%SUMY   Short-hand command to sum over the two last dimensions of N-D matrix
%       and to squeeze it to N-2-D matrix.
% S = sumy(A) is equivalent to S=sum(sum(A,3),2) for 3D matrix for instance.

S = sum(sum(A,ndims(A)),ndims(A)-1);
